The invention relates to methods for the electrical grounding of plastics coated chain link fabric, usually used for fences or similar enclosures but not limited to such applications.
There is a need in the various industries using plastics coated chain link fabric, for fences or other applications, to be able to electrically ground the said fabric.
It should be noted that when the term "plastics coated" is used concerning this invention that an insulating material is intended and the use of other insulating materials other than plastics is included within the scope and intent of this invention.
The need for such electrical grounding is for the purpose of eliminating induced voltages, static charges, and other currents which might occur in such a chain link fabric installation.
Certain installations of chain link fabric, such as in fencing, especially those which are installed near transformer, generating, and other electrical equipment, are subject to induced voltages.
Previously, galvanized chain link fences or fences without insulating coatings would be grounded at intervals along the length of the fence, so that these voltages and currents would be eliminated by grounding through known clamps and known grounding systems.
Chain link fabric is formed in a chain-like system where flattened helixes are woven to flattened helixes. When the wire from which the fabric is woven is insulated, there is no grounding from one helix to the next helix.
It should be understood that the use of the term plastics coated is intended to mean any form of insulation where plastics or other material is used. Such other insulating materials are within the scope and intent of this invention.
Once the individual wires in said helix form that comprise the fabric are grounded or inter-connected to the next helix, and thence throughout the fabric until the entire fabric is inter-connected or grounded together, any charge on the fabric is taken to ground by known means. The fabric is effectively electrically grounded along its entire length at periodic intervals.
When a chain link fabric is woven to various heights for use as fencing, the various heights are obtained by adding "diamonds" (the diamond pattern of the woven fabric.)
Standard heights in the industry are normally woven by weaving a specified number of "diamonds" for the desired height. These heights are not woven with an even number of "diamonds", they are woven with a half of a "diamond" in the height. Having the fabric thus woven, the top of one helix connects to the bottom of its adjacent helix and thereon along the length of the fabric.
With the above pattern of weaving the wires are connected, one to the other, at the "twist" or "knuckle" at the top and then a similar connection at the bottom to an adjacent wire. Thus alternating top and bottom the connection moves down the length of the fabric.
By the use of the inter-connecting or grounding method in this invention through the above weaving method, a continuous flow of current can be obtained down the entire length of the fabric segment. Such a continuous flow can draw off or drain off all induced voltages, static charges, and other electrical currents in the fabric. Thus, taken to ground, the fabric, whether as a fence or in any other use, is effectively, electrically grounded.
In this invention, in which the insulation placed on the wires may be a plastics or other insulating material, the material will be described as a plastics material. The plastics coating placed on the fabric wires is a specially made powder coating which is highly filled with a pulverized conductive element such as, but not limited to, aluminum shavings. The powder filled with these conductive shavings is fused onto the wire, most of the particles of the metal are insulated from each other by a thin layer of the plastics or other insulating material. Whenever "metal shavings" is used, "conductive elements" is implied. For example, carbon elements rather than metal shavings may be used.
These highly filled coatings do not provide a conductive continuity. An arc-over must occur between one metal core to the next metal core of the fabric helix wires in order to provide a permanent conductive path between the metal particles and link one metal core to the next metal core.
In the arcing between the conductive particles a conductive path forms through the plastics or other insulating material by actual transformation of the non-conductive materials which takes place. This change creates a "tree" link between the metallic particles. Once this arc-over takes place, a permanent conductive path is set up.
To obtain the arc, a power source is applied to adjacent wire cores of the helixes, applying a voltage of sufficient magnitude to arc across the insulating layers between each of the pulverized conductive material particles in the insulation and thus forming the permanent conductive path which allows for elimination of induced voltages, static charges, and other currents in a structure of insulated chain link fabric.
It is therefore an object of the invention to provide an effective electrical grounding system for plastics or otherwise insulated chain link fabric when used as fencing or for other similar enclosures.
Another object of this invention is to establish the path of said effective electrical grounding system by use of a chemical-electrical method.
It is another object of the invention to provide a method that can be accomplished during the normal fabric weaving procedure.
Further objects and advantages of the invention will become more apparent in light of the following description of the preferred embodiments.